Do you have a C:\Windows.old folder that could possibly have you old Firefox data?

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

If you do not know the password of the Sync account then you would have to reset the password and a password reset invalidates data stored on the Sync server. Your personal data is encrypted locally using a key derived from the password of the Sync account before it is uploaded and can't be decrypted if the password isn't know or is changed even if you could download this data.

i have a username and password but i dont have email password of my sync account. because i change my password. i set it randomly password. confirmation link not received my side.

If you are saying that you changed the password for your Firefox account, your Sync data is gone.

And if you are saying that you can't access the email account that is registered to your Firefox Account, you're out of luck.

Note you may need to act quickly if you need to get information from the Windows.old folder it may be temporary and deleted after say 30 days.

That folder may contain some Firefox data.

If you used Sync with another device that device should have your data on it, although if it was only an Android phone it will not necessarily have the full data you had on Firefox Desktop.